Phosphodiesterase-5 Inhibitor in Eisenmenger Syndrome

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government.
Read our disclaimer for details.

The primary end point of efficacy was improvement in exercise tolerance as assessed by the un-encouraged 6 minute walk test (6MWT) compared to baseline after 6 weeks of treatment [ Time Frame: 6 weeks ]

A preliminary observational study by the investigators has shown that tadalafil, a selective phosphodiesterase-5 inhibitor (PDE-5) decreases pulmonary vascular resistance(PVR) in patients of eisenmenger syndrome (ES) resulting in increase in pulmonary blood flow (Qp), systemic oxygen saturation (SaO2), functional class and exercise capacity. The aim of this placebo controlled trial was to assess the effect of the drug on exercise capacity and functional class compared to placebo.

Detailed Description

Methods Patients of ES with age greater than or equal to 18 years and weight greater than or equal to 30 kgs in World Health Organisation (WHO) functional class II and III attending our congenital clinic were invited to participate in the study. Informed written consent was taken from all the patients before screening procedures were initiated for the study. A detailed clinical examination and non-invasive testing including electrocardiogram, chest X ray, pulmonary function tests (to exclude associated restrictive/obstructive lung disease) and echocardiography(including contrast echo if required for demonstrating right to left shunt) were conducted. Patients with simple congenital heart defects (atrial septal defect > 2cm, ventricular septal defect > 1cm and aortopulmonary communications > 0.4 cm) with echocardiographic evidence of right to left shunt were included. Medical therapy and clinical condition of the patients had to be stable for 3 months prior to screening. Patients on treatment with prostanoids, endothelial receptor antagonists (ERA), PDE-5 inhibitors or any other vasodilators with in 1month prior to screening were excluded. A systemic pulse oximetry (SpO2) between 70% and 90% at rest in room air and a baseline 6 minute walk test(6MWT) distance between 150 and 450 meters were required for inclusion. Eisenmenger physiology was confirmed by cardiac catheterization as mean pulmonary artery pressure > 40mmHg, pulmonary capillary wedge pressure < 15mmHg and pulmonary vascular resistance >10 wood units/m2. Oxygen study was also done in selected patients to diagnose reversible pulmonary arterial hypertension(PAH) and such patients were excluded. Patients were also excluded if they were in WHO class IV, were in congestive heart failure or had PCWP > 15mmHg,had left ventricular ejection fraction <40%, atrial fibrillation, patent ductus arteriosus, complex congenital heart defects, restrictive lung disease(total lung capacity < 70% of predicted), obstructive lung disease ( forced expiratory volume in 1 second [FEV1] < 70% of predicted with FEV1/ Forced vital capacity [FVC] < 60%), previously diagnosed coronary artery disease requiring nitrate therapy, abnormal biochemical profile and hypersensitivity to PDE- 5 inhibitors. Left and right heart catheterization was done in eligible patients as described in our preliminary observational study. Calculation of pulmonary and systemic blood flow(Qs), PVR and SVR was performed using the Ficks equation and assumed values of oxygen consumption according to age and gender of patient. The study was conducted according to the most recent amendments to the Declaration of Helsinki and in adherence to good clinical practice guidelines. The trial was approved by the National Drug Regulatory Authority (DCG) and the ethical committee of our institution.

Study design and procedure:

A double blind randomised placebo controlled crossover trial was carried out to study the efficacy and safety of oral tadalafil. Eligible patients were randomised to receive either oral tadalafil or matching placebo after baseline assessment of WHO functional class, exercise capacity by 6MWT and hemodynamic study by cardiac catheterization. Randomisation, blinding and drug/placebo administration was done by two pharmacists of the hospital. Patients received tadalafil 40mg once daily or matching placebo for 6 weeks which was followed by a 2 week washout before crossing over to the other drug for another 6 weeks. Routine medications for PAH like digoxin and diuretics was continued through out the study. Compliance was assessed by the pill count method at 3 weekly intervals. Safety of the drug or placebo was assessed by noting adverse effects, vital signs and (SaO2) by pulse oximetry at 3 week intervals. Clinical assessments (WHO functional class), 6 MWT and hemodynamic parameters by cardiac catheterization were reassessed after 6 weeks and again at the end of the study.

* Includes publications given by the data provider as well as publications
identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.

Recruitment Information

Recruitment Status ICMJE

Completed

Enrollment ICMJE

28

Completion Date

July 2010

Primary Completion Date

July 2010 (Final data collection date for primary outcome measure)

Eligibility Criteria ICMJE

Inclusion Criteria:

Patients of ES with age greater than or equal to 14 years and weight greater than or equal to 30 kgs in World Health Organisation (WHO) functional class II and III attending our congenital clinic were invited to participate in the study